I have the exact same problem.
All texts (posts, pages, sidebars) beneath the header and breadcrumb were missing (instead all white). However, I figured that everything appears again when I changed to another theme. I eventually deleted the new MaxFlat Core version and re-installed the 1.0.9 version through the admin panel. All normal again. However, I hope the 1.1 version can be fixed at some point. Thanks!